Geologic reservoirs may be used for various purposes such as hydrocarbon production, geothermal production, or carbon dioxide sequestration. These reservoirs are typically accessed by drilling boreholes through the earth to the reservoirs.
A borehole is drilled using a drill bit that is rotated by drill pipes coupled together in series and generally known as a drill string. As the borehole is being drilled, several instruments or tools disposed at the drill string may perform measurements that may be used to monitor drilling operations or characterize the earth formation being drilled. In order to provide these measurements to an operator, processing system or controller disposed at the surface of the earth in real time, these measurements may be transmitted electrically via a transmission line or cable disposed in the drill string. Because drilling fluid is pumped through the interior of the drill string and the drill string is subject to severe vibrations during the drilling process, apparatus and method that protects the transmission line would be well received in the drilling industry.